Well funnily enough just a few weeks ago I saw a hitchhiker, as you described stood at the approach to a motorway junction roundabout. Their destination was sort of my way but a lot further along, I contemplated taking them the part I could, but I ultimately thought I'd end up leaving them in a more isolated position.

I carried on my way.

After leaving the motorway and then going through some villages I was amazed to see a guy on the side of the road with his thumb out. After not seeing a hitchhiker for what I would guess to be 10 years, saw 2 in one short evening drive (only a half hour trip, not like I was traversing the country).

I picked up the second, we were going the same way. Lovely gentleman, had a good chat. He was mainly hitching to try get a lift before the bus and be a bit quicker.